The Role of Cyclic Stress-Strain Behavior on Fatigue Damage Under Varying Load

The stress-strain response for a complex varying load was analysed on the basis of a cyclic stress-strain curve obtained by incremental step stress tests. A new cumulative fatigue damage law was proposed, considering the fact that the cyclic stress-strain curve for complex varying load differs from that for constant amplitude cyclic load. Assuming that local stress-strain behavior at a stress concentration or a crack tip is similar to that of the bulk material, the law was extended to the case of notched specimen, and the extension was verified by experiment.